The accumulation of Li2CO3 in a Li–O2 battery with dual mediators

Abstract

One of the most important challenges facing long cycle life Li–O₂ batteries is solvent degradation. Even the most stable ethers, such as CH₃O(CH₂CH₂O)CH₃, degrade to form products including Li₂CO₃, which accumulates in the pores of the gas diffusion electrode on cycling leading to polarisation and capacity fading. In this work, we examine the build-up and distribution of Li₂CO₃ within the porous gas diffusion electrode during cycling and its link to the cell failure. We also demonstrate that the removal of Li₂CO₃ by a redox mediator can partially recover the cell performance and extend the cycle life of a Li–O₂ battery.